MANHATTAN, Kansas(Kansas State Collegian), April 4, 2008:
A recent study suggests the compression of morbidity and compression of disability might be separate phenomena, making it easier for people to live to age 100.
Photo: Lisle Alderton
Compression involves delaying morbidity or disability so it takes up a smaller percentage of a person's total lifespan. The study was published recently in the Archives of Internal Medicine.
The prevalence of centenarians has increased dramatically during the last 20 years, the study's authors wrote in "Disentangling the Roles of Disability and Morbidity in Survival to Exceptional Old Age." The study's purpose was to determine the absence or presence of disability among centenarian survivors.
Survivors, according to the study, were defined as individuals who developed at least one of the following conditions before age 85: chronic obstructive pulmonary disease (chronic lung conditions that obstruct airways in the lungs), dementia, diabetes, heart disease, hypertension, osteoporosis, Parkinson's disease or stroke. The authors selected age 85 as a cutoff based on the commonly used definition among scholars of the "oldest old."
The New England Centenarian Study was a cross-sectional study (the study took place at a single point in time) of persons 97 years or older who were referred to as centenarians. The centenarians were recruited through mass mailings, local census records and media reports. Data for the analysis was collected through telephone and e-mail interviews. If participants were unable to complete the information themselves, family members or friends assisted with the questionnaire, according to the study.
Data were analyzed from 739 persons - 523 women ages 100-119 and 216 men ages 97-113 were interviewed. Among centenarians, 32 percent were survivors, or those who developed an age-related disease or condition before age 85.
In a telephone interview, lead author Dr. Lara Terry said the study examined physical function and how it relates to the development of chronic age-related diseases and longevity.
"What surprised us was that nearly a third of the participants had an age-related illness for 15 years or more and yet they survived to very old age and, in many cases, they maintained good physical function," she said.
Terry said future research studies should focus on different genetic and behavioral pathways to reach old age.
"What our study suggests is that there are multiple ways to get to age 100-some individuals may make it there in perfect health, some may develop illnesses only at the end of their very long lives, and some may have illnesses for many years and still get there," Terry said. "Similarly, there may be different pathways in terms of physical function."
Gayle Doll is the director of K-State's Center on Aging. Doll's areas of specialization include physical functioning in older adults and issues that affect adults near the end of their lives. She said people often show signs of chronic disease based on their personality traits - the five traits of personality are extroversion, agreeableness, conscientiousness, neuroticism and openness.
"If you have a neurotic personality where you focus on how bad you feel all the time, you're not likely going to live a long time because you're going to be focusing on how bad you feel, and when you focus on how bad you feel, you're going to function worse," Doll said. "As these authors seemed to find, there's a certain group of people that even if they have lots of problems continue to live relatively functional and happy lives."
With the study authors' future research, Terry said they aim to gain an understanding of underlying causes for delayed disabilities in the presence of age-related disease. She said additional research in this area might lead to prevention and treatment methods for disease and disability.
The study's results also suggest that male centenarians maintained better physical and cognitive function than female centenarians. According to the study, these observations might indicate a demographic crossover in which women have better function than men in younger old age. Though older men are fewer in number than women, these observations also indicate men have better function than women in old age.
"Other studies have shown that women are more adept to living with chronic disease and disability than men," Terry said. "Certainly, many more women survive to age 100 than men. However, for the men who do make it to very old age, our study showed that they often do so with better cognitive and physical function than women." One possible explanation for this difference be that men must have excellent health or be functionally independent to achieve old age, according to the study.
The authors noted several limitations in their study. Because the study was cross-sectional and consisted of about 97 percent white U.S. centenarians, the results might not easily generalize to other centenarians, according to the study.
The New England Centenarian Study does not exclude individuals by sex, race, functional ability, cognitive ability and living situation, which might make it difficult to obtain a sample as generalized as possible, according to the study.
"It is possible that our study was biased toward healthier centenarians, but the breakdown of the living situations for the participants suggest otherwise," the authors wrote.
By Adrianne DeWeese
Source: Kansas State Collegian
